1971 A65 which should use the NPSF thread.
the F stands for fuel(s) and the thread seals completely when tightened. Zccordi g to the service sheets the NPS type threads at least should be of the fuels type (aka dry seal) link showing comparison
Hmmm ... I would've said Triumph and BSA used just NPS thread? I understand the mechanics of "Dryseal" but, steel switch screwing into ally, "Dryseal" theory was never going to work in practice for any length of time.
noticed FEKED list the same switch against both Smith's part numbers for the NPSF and the NPTF
Ye-ea-ah ... Feked is scary-bad:-
. '74-on 60-3719
- Veglia? They were made by Smiths before '79, Veglia only made 'em after Smiths stopped. 24 tpi or 26 tpi? Originals were 27 tpi NPS ...
. Apart from that, the Triumph 60-2133 number is just the standard trade confusion. The original Triumph equivalent of BSA 19-6504 was D1943 (60-1943). Used first on the triple engines, first built in June 1968. That is a taper-thread switch.
. Meriden then caused the monumental part numbers confusion by printing D2133 in the '69 twins' parts books but fitting some of their early '69 ones with taper-thread switches. When the Triumph triples changed to straight-thread switches is recorded as January 1969; Meriden issued a new parts book around the same time, with D2133 for the switch ... Meriden failed to record when they changed the twins from taper- to straight-thread but afaict before they started using the date-code-5-figure-number VIN format in October 1968.
. Educated guess says Rocket 3's changed from taper- to straight-thread switch (19-6504 to 19-6508) around the same time as the Tridents; however, is there any record of when the '69 BSA twins did?
Draganfly (where I got mine from) don't distinguish either way.
Draganfly is just confused (reflecting they're fairly recent Triumph and BSA dealers) - if you look at their entry for Triumph 60-2133, it's the same switch as BSA 19-6508 but the 60-2133 entry says it's taper-thread, that - as I say - is just the general trade confusion over the part numbers.
If you want an NPS switch for your '71 A65, order 60-3719 from the confused trade ...
would imagine there is just as much meat on an A65 as there is surrounding the threads on a triumph casing.
Mmmm ... I'm only familiar with the switch position on a '70-on single; if the A65's similar, much more "meat" than a Triumph timing cover.
... gives an idea of how little "meat" there is around a Triumph twin's OP switch hole ...